Graphene coated particles, their method of manufacture, and use

ABSTRACT

Disclosed is a composition of matter comprising a biologically active substance bound to a graphene-coated dielectric-core particle, and methods for making and using the same.

REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of U.S. application Ser. No. 15/932,667(currently pending), which is the national phase application of PCTapplication PCT/US/2017/000014, Filed 15 Feb. 2017, which claimspriority to provisional application 62/296,537, filed 17 Feb. 2016, allof whose contents of which are incorporated herein in their entirety.

TECHNICAL FIELD

The following inventive concepts relate to particles coated withgraphene having chemical groups attached, their manufacture, and use.

BACKGROUND ART

Graphene is a form of carbon characterized by a flat hexagonal aromaticlattice of carbon atoms. Graphene, applied to a substrate in a singlelayer or sheet, is seeing increasing scientific use a basic material inindustrial production and scientific research, due to its interestingelectrical and physical properties. However, there are limits to itscurrent use. Primarily, it is difficult to both apply chemical andelectrical functionalities to bulk graphene and have that “activated”graphene attached to a usable substrate for distribution. Therefore, aneed exists to provide mechanisms to create and distribute suchparticles.

Further, delivering biologically active substances to targets is anever-present problem in the pharmaceutical, herbicide, pesticide,fertilizers, fungicide, and water treatment industries, amongst others.Therefore, a solution to this problem is also sought.

DISCLOSURE OF INVENTION

Embodiments of the present invention may provide for a graphene coated,chemically active particle comprising a silica core, a graphene layersurrounding the core, and negatively charged moieties or basic moietiesattached to the outer surface of the graphene layer.

Embodiments may also provide for a method for creating a biologicallyactive graphene based substrate as provided above, additionallycomprising binding a biologically active peptide to a metal ion, themethod comprising adding graphite to a solution of weak base,neutralizing the solution with a weak acid substance, super-heating thesolution, then immersing a metal in an electrolyte solution with adissimilar metal, neutralizing the electrolyte solution, adding apolypeptide to the metal electrolyte solution, and combining thepeptide/electrolyte solution with the graphene solution.

Embodiments may also provide for a method to bind biologically activemolecules and organisms in-situ to graphene coated charged particles,comprising spraying or soaking the chemically active graphite particlesolutions described above over in-situ biological molecules ororganisms.

Embodiments of the present invention can provide for a method ofmanufacturing a charged, graphene coated particle comprising: addinggraphite to a weak basic solution, neutralizing the solution with a weakacid substance, immersing a metal in an electrolyte solution with adissimilar metal, combining the graphite and metal solutions, adding asilica substrate to the mixed solution, and super-heating the mixedsolution.

BRIEF DESCRIPTION OF THE DRAWINGS

The figures herein are schematic, and are not necessarily to scale.Features may be exaggerated for simplicity or to assist understanding.Skilled practitioners will recognize that some components or steps mayhave been omitted for simplicity, and that other components or steps maybe added without deviating from the underlying concepts disclosedherein.

FIG. 1 is a schematic, cross-sectional view of an example of chemicallyactive graphene/core particle complex, according to some inventiveaspects.

FIG. 2 is a schematic, simplified cross-sectional view of an example ofa metal-attached polypeptide, according to some inventive aspects.

FIG. 3 is a schematic, simplified cross-sectional view of an example ofa metal-attached single cell organism, according to some inventiveaspects.

FIG. 4 is a schematic, simplified cross-sectional view of an example ofa chemically active graphene coated particle complexed with ametal-bound single celled organism, according to some embodiments of theinvention.

FIG. 5 is an example method of fabricating a complex as shown in FIG. 4.

FIG. 6 is an illustration of an example method for generating achemically active graphene coated particle.

FIG. 7 is an illustration of an example method for generating ametal-bound polypeptide or organism according to embodiments of theinvention.

BEST MODE FOR CARRYING OUT THE INVENTION

The inventive concepts disclosed herein are described with respect toparticular example embodiments and processes along with someexplanations for their operation, however, one skilled in the art willrecognize that the underlying principles disclosed may be embodied inother examples or methods not necessarily identical to the givenexamples. Therefore, the limits of the inventive concepts are to betaken as the claimed subject matter, and not the individual examplesthemselves.

Shown in FIG. 1 is a simplified cross-sectional view of an example of achemically active graphene coated particle 100 (sometimes referred tobriefly as a graphene coated particle 100) according to aspects of theinventive concepts. The example complex can be described as a coreparticle 102 that is coated with a graphene shell 104 having chemicallyactive groups 106 attached to the graphene. In some embodiment, thechemically active groups 106 may be negatively charged or basic groupson the graphene shell's outer surface.

The core material used herein is an inert material that exhibitsdielectric properties. More particularly, in some embodiments, the coreparticle 102 may be a silica (or mostly silica) structure such as finelydivided and screened silica, diatomaceous earth, coal, or other similarlargely inert material. The chemically active group 106, such as thee.g. negatively charged or basic group may be evenly or unevenlydistributed over the graphene shell 104 (depicted here as a layer due tothe relatively small nature of the groups). The physical structure ofthe core material may be non-uniform and may contain multiple flatsurfaces where the surfaces are multi angled, and/or multi-dimensional.In some embodiments, the negatively charged or basic group (chemicallyactive group 106) may be a hydroxy group. The construction of grapheneparticle 100 will be discussed below with regard to FIG. 6.

Shown in FIG. 2 is a simplified cross-sectional view of an example of ametal-attached polypeptide 108, according to aspects of the inventiveconcepts, which may be comprised of a polypeptide or protein 110, andmetal ion 112 bound to its active site, in some instances imparting anoverall positive charge (or regional or “local” positive charge) to thepolypeptide 108. In some embodiments, multiple metal ions may be boundby a polypeptide, or multiple polypeptides may bind a single metal ionin concert. The polypeptide 110 may be a stand-alone polypeptide orprotein, or one attached to an organism (such as being part of anorganism's cell wall or outer membrane), which is depicted in FIG. 3.

Shown in FIG. 3 is a simplified cross-sectional view of an example of asingle cell organism 116 having at least one protein 110 holding a metalion 112 (i.e., a metal-attached polypeptide 108), the complex of whichis referred to as a biologically active organism/“charged cell” complex118 (although the charge may be local only). The metal-attachedpolypeptide 108 may be located approximately on the outer surface of asingle celled organism 116, such as in the outer membrane or cell wall.The single celled organism 116 may be an organism such as a prokaryoteor eukaryote, and these may have a one or more metal-attachedpolypeptides 108, on their surface at multiple locations. Alternatively,the charged cell 118 shown in FIG. 3 may be part of a multi-cellorganism, with the other cells not shown for clarity. For the sake ofclarity, 118 will be referred to as “charged cell” 118. The delivery ofmetal ions to the polypeptide, and its relationship to the grapheneparticle 100 will be discussed below.

Shown in FIG. 4 is a simplified cross-sectional view of an example of agraphene particle 100 bound to a cell 116 having at least onemetal-attached polypeptide 108 (hereinafter “complex 114”), according toaspects of the inventive concepts. More specifically, the complex 114can comprise a graphene-coated core particle 100 as depicted anddescribed in FIG. 1, chemically bound (through ionic, covalent, or otherchemical binding means) to the metal of the metal-attached polypeptide108 (depicted and described in FIG. 2), which in turn may be stand-aloneor located on a cell 110, the state of which is depicted and describedin FIG. 3 as the charged cell 118.

In some embodiments, the complex 114 can be produced by combining themetal-attached polypeptide 108, or charged cell 118, together with thechemically active graphene complex 100, each of which holds respectiveionic charges: 112 (a positive charge or metal ion, such as one or moreof the transition metals of manganese, iron, copper, zinc, etc.) and 106(a negative charge or base, such as a sodium, potassium, or ammoniumbase salts) that are attracted towards one another.

More specifically, in some embodiments, the positively charged metal ion112—which gives the polypeptide 110 located on charged cell containingorganism 116 (or overall, the charged cell 118 possessing polypeptide110) its charge—binds at the active site[s] (“receptors”) of thepolypeptide 110. Meanwhile, the negatively charged/basic surface coating106 on the charged graphene complex 100 is a chemical component attachedto graphene shell 104 of graphene particle 100. These two componentsattract each other to form overall complex 114.

In some embodiments, there may be a multiplicity of metal-boundpolypeptides 108 or charged cells 118 complexed with each graphenecoated particle 100. In other embodiments, each charged cell 118 mayhave multiple graphene coated particles 100 complexed with it. Thedistribution of the chemically graphene complexes 100 over the surfaceof a charged cell 118 may be uneven, depending on the attraction betweenthe polypeptide 110 located on the single charged cell 118 and thecharged graphene complex 100, and on the physical location ofmetal-attached polypeptides over the surface of the cell. A process ofproducing the final complex 114 is described in FIG. 5.

Shown in FIG. 5 is high-level example method of fabricating complex 114,according to aspects of the inventive concepts. In process 600, achemically active graphene coated particle 100 is fabricated. Thisprocess is elaborated on in FIG. 6, below. At process step 700, ametal-attached polypeptide or single-celled organism 108 is produced.Details of this process are further described in FIG. 7. In process step800, the complex 114 is created by combining the charged graphene coatedparticle complex 100 produced in process step 600 with themetal-attached polypeptide 108 or charged single cell organism 118produced in process 700. The graphene coated particle 100 may act as adelivery mechanism for a polypeptide 110 or single celled organism 116when combined into a complex 114. Alternatively, in some embodiments,the method for creating complex 114 may be used to precipitate out, orotherwise bind to biological entities (such as mold spores) in theenvironment.

Shown in FIG. 6 is an example method 600 for producing a chemicallyactive (negatively charged, or basic) graphene coated particle complex100 according to aspects of the inventive concepts. The method 600 mayconsist of a step 604: pulverizing graphite, a step 606: adding to areducing solution graphene and core particles 110, where in during theresulting REDOX reaction the resulting oxygen is off-gassed anddepleted, a step 608: neutralizing the mixture of 606, and 614:superheating the mixture of 608 to create the chemically active graphenecoated particles 100.

More specifically, in some embodiments, the core particle 102 may be anytype of inert, dielectric material and may include, for example, silica,coal, or diatomaceous earth. At step 604, in some embodiments, thegraphite can be milled to 0.5 to 10 micron sized particles. In someembodiments, at step 606 the pulverized graphite can be immersed withthe core particles in a reducing solution of sodium hydroxide diluted to5 to 10 mol, and combined with ammonia. The immersion time of this stepmay be about 10 minutes to an hour. In some embodiments, the solution iscooled overnight at room temperature in a water bath, dry-ice or adry-ice/acetone bath to control the temperature of the reaction. Afterthe immersion mixture is cooled to room temperature, nitrogen gas may bebubbled into the solution used to reduce any resulting oxygen.

In some embodiments, at step 608, the mixture's pH can then beneutralized or adjusted to a pH of 6.0-7.0 by a sodium or potassium basesalt or ammonium salt, or the like, thus producing a hydroxide ion thatimparts a negative charge to the graphene. The mixture is thensuperheated in step 614 to produce the charged graphene-core particlecomplex 100. The heating method may be a microwave or other heat source.

The result of example process 600 is a core particle coated withgraphene having negatively charged or basic groups attached: a chargedgraphene coated particle complex 100. Without being limited by theory,the charged graphene coated particle complex 100 resulting from step 614may comprise of a core 102 that is coated with a graphene shell 104 thatcarries for example, a basic hydroxy group 106 that may attract thepositively charged metal ion(s) 112 of the charged polypeptide orsingle-celled organism 108. This graphene coated complex 100 is capableof holding a negative electrical or chemical charge or basic group 106,and has the capacity to attract, bind and potentially become a carrierfor a positively charged (or metal bound) polypeptide 108 orsingle-celled organism 118.

Shown in FIG. 7 is an example method 700 for generating metal-attachedpolypeptide 108 or single celled organism 118 according to aspects ofthe inventive concepts. In some embodiments, the process of producing ametal-attached polypeptide 108 or single cell organism 118 is conductedat room temperature, and consists of a ion generation process 720conducted at 60-100 F (10-37.8 C) degrees temperature, which consists ofan electrolyte solution producing step 712, a dissimilar metal immersionstep 714, and a solution neutralization step 716. Process 720 isfollowed by step 718, where a polypeptide 106 or single celled organism110 is added into the metal ion solution produced in step 716 togenerate the metal-attached polypeptide 108 or single-celled organism118.

More specifically, in some embodiments, in step 712, an electrolytesolution is produced. The dilute electrolyte solution may be made with aratio of 1:10 up to 1:100 acid to water. The acid may be phosphoric,sulfuric, hydriodic, or hydrochloric acid, or a weaker acid such ascitric or acetic acid, or a combination of acids (see Table 1, below).The pH of the electrolyte solution may be under 4.0. At step 714, twometals of dissimilar electrical potential and biological importance,such as transitional metals like Cu and Mn may be dissolved in theelectrolyte solution. The metals added during step 714 are in the formof large particles, or are milled, ground, or screened 1 to 10 micron orlarger sized particles. After the metals are dissolved in theelectrolyte solution, the solution's pH may be raised to about 6-7 instep 716, by adding a sodium or potassium base salt (such as sodiumhydroxide), or the like in step 714, which produces a positively chargedmetal ion solution. The poly peptide 110 or single-celled organism 116is then imbued with charged metal ion 112 by immersing a solution of thepolypeptide in the metal ion solution in step 718. In alternativeembodiments, step 718 may be carried out with a suspension of singlecelled organism 118 having on them polypeptides 110 that are capable ofbinding a charged metal ion. Without being bound by theory, theresulting complex produced in step 718 can be a charged polypeptide orsingle celled organism 108, which may comprise of a polypeptide 110 orsingle celled organism 116 with a with a positively charged ion 112attached to it at a receptor site.

Returning to FIG. 5, once the graphene coated particles have beenprepared according to process 600 of FIG. 6, and the metal-attachedpolypeptides 108 or single-celled organisms 118 have been prepared, thetwo can be combined at step 800 to produce complex 114 of metal-attachedpeptides (or organisms) attached to graphene coated particles.

In alternative embodiments, complex 114 may be produced in analternative way. Before being added to the ploy-peptide 110 orsingle-celled organisms 116 at step 718, the electrolyte solutionprepared in process 720 may instead be added directly to the grapheneparticles produced as a result of process 600. This produces acomposition consisting on a graphene coated particle with a basicsurface coating which is in turn bound to the metal ions of the solutionprepared in 720. This new mixture may be sprayed, soaked or otherwiseapplied to the environment to bind to polypeptides 110 or single celledorganisms 116 (such as mold spores) in the environment in-situ,producing complex 114. If the mixing is performed in environmentalwater, this may result in a purification of the water.

It has been observed that creating the complex 114 in-situ as describedabove causes mold spores, bacteria, and other microscopic biologicals toaggregate and come out of suspension in air and water, making itsubstantially easier to clean or disinfect surfaces.

Furthermore, it has been observed that spraying the solution of complex114 results in a surface coating of the complex 114 on the target ofspraying or immersing that is both even and resistant to removal. Thus,creating and applying a complex of 114 wherein the polypeptide 110 hasbiologic activity (such as a pesticide) may be an effective mechanism ofdistributing such biologically active polypeptide and effectuating itspurpose.

TABLE 1 sample basic and acidic solutions applicable to the processesherein: pH pH pH Anode- oxidation 1 mM 10 mN 100 mM ALKALI SOLUTIONSPotassium hydroxide (KOH) 10.98 11.95 12.88 Sodium Hydroxide (NaOH)10.98 11.95 12.88 Sodium Metacilicate (Na2SiO3) 11.00 11.91 12.63Ammonium hydroxide (NH4OH) 10.09 10.61 11.13 ACID SOLUTIONS Strongeracids Sulfuric acid (H2SO4) 2.75 1.87 1.01 Hydrochloric acid (HCL) 3.012.04 1.08 Phosphoric acid (H3PO4) 3.06 2.26 1.63 Weaker acids Citricacid (C6H8O7) 3.24 2.62 2.08 Lactic acid (C3H6O3) 3.91 3.39 2.88 Aceticacid (C2H4O2 3.91 3.39 2.88

We claim:
 1. A graphene coated particle comprising an inert core, onwhich sits a graphene coating, which graphene coating has negativelycharged or basic groups on its outer surface.
 2. The compositionaccording to claim 1 additionally comprising metal ions bound to thenegatively charged or basic groups.
 3. The composition according toclaim 2 additionally comprising a polypeptide bound to the metal ions.